Amethyst is a purple variety of quartz and owes its violet color to irradiation, impurities of iron and in some cases other transition metals, and the presence of other trace elements, which result in complex crystal lattice substitutions.
Amethyst is said to be incredibly protective, healing, and purifying. It's claimed it can help rid the mind of negative thoughts and bring forth humility, sincerity, and spiritual wisdom. It's also said to help promote sobriety.
Amethyst reminds us to treat the body and mind as a sacred temple. It helps us unplug from unhealthy attachments, and powerfully cleanses the body, mind and aura from negative or addictive patterns. A stone of protection, amethyst creates an ultraviolet bubble of protective light around people and spaces, and is very helpful for insomnia and nightmares.
From Crystals The Modern Guide to Healing. By Yulia Van Doren Goldirocks
These amethyst towers are from Brazil.